4 built-in data types

In Python, lists, sets, tuples, and dictionaries are used to store collections of data. Each has different properties and use cases.

• set: an unordered, mutable collection that does not allow duplicates.
  It can contain different data types:
  ✅ (Integers, floats, strings, tuples (if the tuple only contains immutable types)
  ❌ not lists, dictionaries, sets (since they are mutable).
  
  Use sets to store unique items and to perform mathematical set operations.

# a set can contain different data types as long as they are immutable
my_set = {1, "hello", 3.14, (1, 2, 3)}

# 'set' object is not subscriptable
print(my_set[1]) # error message

my_set = {1, 2, 3, 2, 1}
print(my_set)  # {1, 2, 3} (duplicates removed)

# adding or removing elements
my_set.add(5)  # {1, 2, 3, 5}
my_set.update([6, 7]) # {1, 2, 3, 5, 6, 7}
my_set.remove(7) # {1, 2, 3, 5, 6} (raises error if not found)
my_set.discard(10) # {1, 2, 3, 5, 6} (# No error if 10 is not found)

# set operations
set1 = {1, 2, 3}
set2 = {3, 4, 5}

set1.intersection_update(set2)
print(set1) # {1, 2}

set1.difference_update(set2)
print(set1) # {3}

print(set1 | set2)      # Union → {1, 2, 3, 4, 5}
print(set1 & set2)      # Intersection → {3}
print(set1 - set2)      # Difference → {1, 2}
print(set1 ^ set2)      # Symmetric Difference → {1, 2, 4, 5}
print(len(set1 & set2)) # 1

set1 = {1, 2, 3}
set2 = {1, 2}

set1 = {1, 2, 3}
set2 = {1, 2}
set3 = {3, 4, 5}
set4 = {4, 5}

set2.issubset(set1) # True
set1.issuperset(set2) # True
set3.issubset(set1) # False
set1.isdisjoint(set3) # False
set1.isdisjoint(set4) # True

# since sets are unordered, pop() removes a random element from the set
set1.pop()

# real world example
engineers = {'John', 'Jane', 'Jack', 'Janice'}
programmers = {'Jack', 'Sam', 'Susan', 'Janice'}
managers = {'Jane', 'Jack', 'Susan', 'Zack'}

# union
employees = engineers | programmers | managers
print(employees) # {'Sam', 'Jack', 'John', 'Zack', 'Susan', 'Janice', 'Jane'}

# intersection
engineering_management = engineers & managers
print(engineering_management) # {'Jack', 'Jane'}

# difference
fulltime_management = managers - engineers - programmers
print(fulltime_management) # {'Zack'}

employees.issuperset(engineers) # True

# add
engineers.add('Marvin') # {'John', 'Jack', 'Janice', 'Marvin', 'Jane'}

employees.update(engineers)
print(employees) # {'Sam', 'John', 'Jack', 'Zack', 'Susan', 'Janice', 'Marvin', 'Jane'}

for group in [engineers, programmers, managers, employees]:
  group.discard('Susan') # remove element if present
  if group == engineers:
    print(f"engineers: {group}")
  elif group == programmers:
    print(f"programmers: {group}")
  elif group == managers:
    print(f"managers: {group}")
  elif group == employees:
    print(f"employees: {group}")
# engineers: {'Jack', 'John', 'Janice', 'Marvin', 'Jane'}
# programmers: {'Sam', 'Janice', 'Jack'}
# managers: {'Zack', 'Jack', 'Jane'}
# employees: {'Sam', 'John', 'Jack', 'Zack', 'Janice', 'Marvin', 'Jane'}